Autoelectronic triode device



Nov. 6, 1934. J. E. LILIENFELD AUTOELECTRONIC TRIODE DEVICE Filed Oct. 3, 1928 anvewtoi Julia? Ed arL zenfeld 32,1 M4 aumwflwg ibb Patented Nov. 6, 1934 UNITED STATES PATENT OFFICE The invention relates to vacuum tubes, more especially of the auto-electronic or non-thermic type.

It has for its object a novel tube of this character which may be caused to operate as a source of X-rays, or as an oscillator and transmitter device of the continuous wave type. i

In carrying out the invention, provision is made for a point discharge of electrons between two cold electrodes and for an associated magnetic field whereby said electrons, or at least the greater portion thereof, are diverted to a third electrode. This latter electrode is to be maintained at a potential positive with respect to the cathode potential but less positive than the anodepotential; and said third electrode may be in the nature of a metallic cylinder constituting then a portion of the enclosing envelope of the tube.

When utilized as an X-ray emission device, as in operating the same at sufficiently high voltage, a suitable window may be provided this cylinder through which said rays may pass to the outside from the point at which they are generated on the anode. This window may serve, also, to allow of viewing the action within the tube.

As a generator of alternating current, the tube may operate as an externally excited or a selfexcited device to generate suitable oscillations.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawing, in which:

Fig. 1 illustrates in elevation and part vertical section the novel vacuum tube.

Fig. 2 is a diagrammatic view illustrating the circuit connections when operating the said tube as an externally excited generator of oscillations. Fig. 3 is a further diagrammatic view illustrating the connections for a tube operated as a self-excited generator of oscillations and provided with means for transmitting the same externally.

Referring to the drawing, more particularly Fig. 1 thereof, 10 designates a suitable glass tube member of which a portion is constituted by a metallic cylinder 11, said tube forming an evacuated envelope for retaining two electrodes constituting the cathode 12 and anode 13 of said tube.

In accordance with the particular character ,of tube, to wit: an auto-electronic or non-thermic type, the cold cathode is formed of one or more externally sharp points which are prefer- .ably made by etching a tungsten or tantalum is disposed opposite the cathode at a distance of the order of magnitude of approximately five millimeters. These two electrodes are located axially within the .metallic cylinder 11 which constitutes a third electrode, as is hereinafter more fully set forth. When a comparatively high voltage is applied across said anode and cathode, for example, from the source of potential 15, 16, electrons will be emitted by the latter, as more particularly 'set forth in my prior U. S. Letters Patent No. 1,559,714.

Connection is made, to this end, from the negative side of said source of potential as through the lead 17 to a tubular member 18, as of nickel, and a cap 19 of molybdenum threaded over its inner end and perforated axially to receive the cathode 12 which may also be threaded therein for adjustment purposes. This threaded end of the cathode, however, is radially cut through to afford communication between the interior of tube 18 and the interior of the 8G vacuum tube proper.

A further lead 20, preferably of tantalum, tungsten, or molybdenum, extends through said tube 18 substantially in the longitudinal axis thereof, being connected at its inner end to the cathode l2 and at its lower end connected to a rod 21 which is centered by a glass hook 22 or like centering device, while a spring 23 maintains the said wire 20 under suitable tension. A lead 24 connected of the vacuum tube provides for electrical connection to a further source of external potential (not shown) whereby a current may be passed by means of said lead 24 and the cathode lead 17 to heat the wire 20 to a high temperature for the purpose of degasifying the cathode 12 in the initial operation of working the tube.

Within the bottom of the vacuum tube or portion thereof constituted by the portion 18, a quantity of caesium may initially be provided, the vapors of which when the tube is thus heated entering the vacuum tube proper through the openings or cuts in the threads of the cathode cap 19. It will be understood, of course, that these operations are only temporary and occur merely at the initial operation or forming of a tube for the purpose of providing the desired physical condition of the surface of the cathode.

In accordance with the invention, the elec-- trons emitted by the cathode 12, or at least the no to the rod 21 and passing out 90 greater portion thereof, are not permitted to strike the anode but are arranged to be deflected to the cylinder 11. This is accomplished by providing about said cylinder magnetic means, as the suitably energized electromagnet 30; and by setting up a ,comparatively strong field, depending on the geometrical dimensions of the tube, the bulk of said electrons will be deflected toward the said cylindrical third electrode. The latter is kept at a voltage positive with respect to the cathode 12 but less positive than the anode 13, a lead 31 to this end connecting the cylinder 11 to an intermediate point of the source of potential supply 15, 16.

It is to be noted, also, that secondary and deflected electrons eventually coming from the anode, particularly when the latter is more or less convex, will also be drawn by the magnetic field to the third electrode and will thus add to the efiiciency of the instrument.

In the hereinbeiore described arrangement, the said anode will act identically as the grid of the present well known thermionic vacuum tube; and it may be externally excited from a suitable source of alternating current (not shown) through the leads 32 coupled thereto by a transformer 33.

If the tube is to be utilized as an X-ray emission device, as in operating the same at sufiiciently high voltage, there is provided in the electrode or cylinder window 34 of glass and through which the emitted rays may pass to the outside and through which, also, the action of. the tube may be viewed.

The tube may also be forced to generate oscillations by a self-excited circuit, reference being had to Fig. 3 of the drawingin which the tube electrodes 11, 12 and 13 are located, as aforesaid, in a magnetic field produced by the electromagnet 30.

The energy in the present embodimenthas been shown as derived from a pair of generators 35 and 36 with an auxiliary inductance 37 included in circuit to obviate short-circuiting of the high' frequency oscillations, and a key 38 or similar modulating device is also included in the circuit for control of the oscillations.

In this self-excited embodiment, the oscillating circuit is constituted by the two condensers 40, 41 and the coupling inductance 42 for outgoing oscillations, as through the antenna 43. The said oscillating circuit also includes two stationary inductances 44 and 45 located at right angles to each other, the field of which inductances acts electro-magnetically upon a rotatable inductance 46. This rotational adjustment enables an operator to secure a proper phase relation on the anode 13, with which it is included in circuit, to obtain the best conditions for selfexcitation.

I claim:

1. In an electrical discharge device embodying an autoelectronic cold anode and cold cathode and means to apply a potential across the same sufiicient to effect a purely electronic discharge from the latter: an electrode associated with said anode and cathode, means to maintain the electrode more positive than said cathode, and magnetic means located in proximity thereto to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said electrode.

2. In an electrical ing an autoelectronic cold anode discharge device embodyand cold cath- 11 a suitable transparent ode and means to apply a potential across the same sufficient to effect a purely electronic discharge from the latter: means associated with said cathode to initially elevate its temperature to an extent to degasify the same, an electrode associated with said anode and cathode, means to maintain the electrode more positive than said cathode, and magnetic means looted in proximity thereto to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said electrode.

3. In an electrical discharge device embodying an autoelectronic cold anode and cold cathode and means to apply a potential across the same sufiicient to eiiect a purely electronic discharge from the latter: an electrode comprising a metallic cylinder surrounding said anode and cathode, means to maintain the cylinder at a potential more positive than said cathode, and magnetic means about said cylinder to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said cylinder.

4. In an electrical discharge device embodying an autoelectronic cold anode and cold cathode and means to apply a potential across the same sufiicient to effect a purely electronic discharge from the latter: an electrode comprising a metallic cylinder surrounding said anode and cathode and constituting a portion of the enclosing housing of said device, means to maintain the cylinder at a potential more positive than said cathode, and magnetic means about said cylinder to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said cylinder.

5. In an electrical discharge device embodying an autoelectronic cold anode and cold cathode and means to apply a potential across the same sufiicient to efiect a purely electronic discharge from theylatterz an electrode comprising a metallic cylinder surrounding said anode and cathode and having a transparent window located in proximity to the same to expose the cathode, means to maintain the cylinder at a potential more positive than said cathode, and magnetic means about said cylinder to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said cylinder.

6. In an electrical discharge device embodying a sealed evacuated envelope having a wall portion thereof constituted by a metal cylinder and an unheated autoelectronic cathode and unheated anode and means to apply a potential across said anode and cathode sufficient to effect a purely electronic discharge from the latter: means to apply a potential to the metallic cylinder higher than the cathode potential but lower than the potential of said anode, and magnetic means about said cylinder to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said cylinder.

7. In an electrical discharge device embodying an autoelectronic cold anode and cold cathode and means to apply a potential across the same suificient to effect a purely electronic discharge from the latter: an electrode associated with said anode and cathode and more positive than the latter, magnetic means located in proximity thereto to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said electrode, and means to vary the potential applied across the said anode and cathode.

the latter, magnetic means located in proximity thereto to provide a magnetic field whereby electrons emitted by the said cathode will be diverted to the said electrode, and an oscillating circuit connected with the anode.

JULIUS EDGAR LILIENFELD. 

